1. Technical Field
The present invention relates generally to aircraft gas turbine engine and aircraft cooling and, more specifically, to such systems for cooling aircraft power and thermal management systems and gas turbine engine turbines.
2. Background Information
Military aircraft designs are being developed with engines that will operate at much higher overall pressure ratios than today's engines. Cooling air for hot sections of the engine's turbine, particularly, the high pressure turbine will be needed. It is known to use compressor air to cool the turbine such as disclosed in U.S. Pat. Nos. 4,187,675, 4,254,618, 7,823,389. Cooling air for aircraft avionics and other airframe cooling requirements may also be supplied by the compressor. The Lockheed F35 has included integrated power and cooling systems also referred to as power and thermal management systems which use compressor air.
U.S. Pat. No. 7,624,592 discloses a power and cooling management system configured to flexibly couple various adaptive modules to an integrated power and cooling unit to suit any aircraft platform is provided. The integrated power and cooling unit has a compressor(s), power turbine(s), cooling turbine(s) and integral starter generator(s) mounted to the shaft of the power and cooling turbine. The integrated power and cooling unit may be pneumatically and/or pneumatically coupled to an adaptive module that comprises an additional compressor and an additional turbine or electrically coupled to a fuel cell which provides the main power after entering the full operation mode. When the engine includes an integral starter generator mounted thereto, the integral starter generator of the integrated power and cooling unit is operative to receive electric power from the engine mounted generator. Alternatively, a motor/generator may be mounted to the shaft of the additional turbine of the adaptive module.
Other examples of integrated power and cooling systems discussed in U.S. Pat. No. 7,624,592 include U.S. Pat. Nos. 4,684,081, 4,494,372, 4,684,081, 4,503,666, 5,442,905, 5,490,645, 6,415,595, and 6,845,630. The inventors of U.S. Pat. No. 7,624,592 found that these designs were complex and wanted to reduce the complexity of the engine configuration and its integrated power and cooling systems.
Typically, these cooling systems use fan cooling air.
Thus, there is a need to supply cool compressor air for both turbine and avionics and other aircraft or airframe required cooling. There is also a need to make such a cooling system as simple and light weight with a minimal effect on fuel specific fuel consumption (SFC) as possible.